1. Field of the Invention
The present invention relates to an endoscope apparatus having a switching switch capable of being switched to a mode in which a curvature operating lever is returned to a predetermined position and a mode in which the curvature operating lever is not returned to the predetermined position, when a hand is released from the curvature operating lever.
2. Related Art and Prior Art Statement
In recent years, there is widely utilized an optical type or electronic type endoscope in which an elongated insertable section is inserted into a body cavity and whereby internal organs within the body cavity are observed and a treating or processing tool inserted into a processing tool channel is so used as to be able to effect various kinds of medical treatments.
In the endoscope, there has been proposed an arrangement in which a curvature portion of the insertable section is curvature-driven by such driving means as an inputting means, motor or curvature operating switch to improve the operability.
For example, in Japanese Patent Unexamined Publication (Laid Open) No. SHO 61-106125, there is disclosed a technique in which a joy stick of an input unit in which grasping or gripping a curvature angle and controlling a curvature speed can be simultaneously effected is brought to a curvature operating switch and upward, downward, leftward and rightward curvature operations are effected by operating the curvature operating switch.
Here, generally, the joy stick is sectioned into two sections by the operation of the (curvature) operating lever. The first of them is a "joy stick of a type having a neutral return" in which, when the hand is separated from the operating lever, the operating lever will forcibly return to the center and the curvature portion will also return to be straight. The second of them is a "joy stick of a type having no neutral return" in which, even when the hand is separated from the operating lever, the operating lever will not move and the curvature portion will maintain the curvature state as of just before the hand is separated. When the joy stick is considered as a curvature operating switch of an endoscope, it will be convenient to have both of the functions of the above mentioned two joy sticks.
In case the curvature portion is required to remain curved as, for example, in a living body inspection, the "joy stick having no neutral return" which will not move even if the hand is separated from the operating lever will be desirable. However, when the insertable section is to be inserted into such narrow tube cavity as of a large intestine, the "joy stick of the type having the neutral return" in which the curvature portion can be quickly straightened will be desirable.
Further, in recent years, there is a prior art having an automatic inserting mechanism in which an insertable section is automatically inserted into a body cavity. This prior art has a detecting means for a dark part within the body cavity by which the insertable section is inserted toward a deep portion while controlling the curvature of the curvature section with the output of this detecting means.
In case the automatic inserting mechanism is to be switched to a manual insertion, if the curvature state of the curvature section by the automatic insertion as of just before the switching does not coincide with a curvature indicating value by the curvature operating joy stick (that is to say, if an inclined direction and an inclined angle do not coincide with each other), the curvature section will be curved by a curvature driving means so as to coincide with the curvature indicating value of the joy stick. By this curvature operation, there is considered a danger of impacting or injuring a body wall. Therefore, it is required to prevent such dangerous situation from being generated.